Grain Silos and Flour Mills Organization ( GSFMO ) of Saudi Arabia is in charge of receiving farmer's annual yield of wheat grain that meet the standard specification established for wheat grain acceptance . In 1988 and 1989, 96 and 93 % of the total wheat samples delivered were accepted respectively. Exceeding dockage content ( max. limits 12 % ) was the most important reason for rejection, followed by insect infestation. The major components of dockage were barley ( 39% ) , wheat broken kernels ( 22.5 % ) , shrunken kernels ( 19.2% ) , and weed seeds ( 15% ) . Four beetles species were detected in the infested samples . The most commonly occurring species was Tribolium castaneum ( Herbst ). The number of insects per 1 kg relatively low and was correlated with period of storage, and percentage of dockage. A discriminate analysis was used to differentiate between free infested and infested samples on the basis of five discriminating variables (moisture content, dockage, test weight, protein content, and the length of storage in weeks ) . The accuracy of this formula was 89.9 - 100 % and 84.6 - 86.3 % for free infested and infested samples respectively . The percentage of moisture content of wheat grain was the most powerful factor in distinguishing the infested from free infested samples followed by dockage, test weight, protein content , and period of storage